Resources Flashcards
what resources do humans use
warm , shelter , food ,transport
how does agriculture help
helps to use the earth’s resources more efficiently
what is a finite resource
resources that cannot be replaced as quickly as being used up
what are examples of finite resources
- fossil fuels
- metals
- plastics
what are examples of renewable resources
wood
solar energy
hydropower
what does sustainability / sustainable development mean in terms of chemistry
meeting our needs without preventing future generations from meeting theirs
Give examples of natural resources and how they are used AND STATE the artifical alternative for each product
- wool - used for clothes and carpets, alternative synthetic product is acrylic fibre
- cotton - used for clothes, alternative synthetic product is polyester
- silk - used for clothes, alternative synthetic product is nylon
- rubber - used for tyres, alternative synthetic product is various synthetic polymers
- wood - used for construction, alternative synthetic product is PVC
what is potable water
water that is safe to drink
why is potable water not classified as pure water
because it contains dissolved substances.
what features should safe drinking water for humans have
drinking water should have sufficiently low levels of dissolved salts, and microbes
what source in the UK is our potable source
- rainwater - as it contains low levels of dissolved substances
where does rainwater collect
in the ground, lakes, and rivers = good sources of fresh water
what are the steps to produce good potable water
- choose a source of fresh water, such as a river ( the fresh water has low levels of dissolved minerals)
- pass the water through filter beds - this is to remove materials such as leaves, and suspended particles
- sterilise the water, to kill microbes
- in the uk, chlorine is used to sterilise the water
- other sterilising agents used ozone, and ultraviolet light
when is the process of desalinating water used
In countries where the main source of water is salty water = it contains high levels of dissolved substances
what does desalination do
reduces the levels of dissolved minerals down to an acceptable level for potable water
what are the ways to desalinate water
- by distillation
- by passing water through membranes, known as reverse osmosis
what is a disadvantage of distilation and reverse osmosis
very expensive as lots of energy is required
describe the required practical experiment to check for pure water
1) check the pH of the water - pure water has a pH of 7 (neutral)
2) this can be done by adding a small amount of the water to a universal indicator paper, which will turn green if the pH is 7
3) even if the pH is 7, the water still may not be pure, so testing for dissolved solids is now needed
4) use a balance to weigh an empty evaporating basin, and record the mass
5) fill basin with water, and place it onto a tripod and gauze, with a bunsen burner
6) use the bunsen burner to gently heat the water, until all water has evaporated, and allow the basin to cool
7) weight the evaporating basin again - if the mass increases, the water must have evaporated but left some crystals at the surface of the evaporating basin contained dissolved minerals = water was not pure
8) BUT IF THE MASS of the evaporating basin didnt increase = water didnt contain any dissolved solids = pure susbstance
describe the steps for the purifying water by distillation practical
- the apparatus has a conical flask, containing the water sample, on a tripod and gauze, with a delivery tube connected to the top of the flask, leading into a test tube, sitting in ice and water
1) gently heat the water, using a bunsen burner, so the water boils gently
2) the water will evaporate and form steam, and the vapour will travel along the delivery tube
3) when the water vapour enters the cold test tube, it will condense back into liquid water
- produced will be distilled water, which has no dissolved solids, and a pH of 7, meaning it is pure water
what must be done to sewage and agricultural waste before it is released into environment
require removal of organic matter, and harmful microbes, before being released into the environment
what are the steps required for treating wastewater
In the first stage, the sewage is screened by passing through mesh to remove large materials eg solids and grit
- the sewage then settles in sedimentation tanks, to produce sewage sludge, and liquid effluent
- The sludge is taken away into separate tank and digested by anaerobic bacteria ( by closing tank lid ) . In the absence of oxygen, the bacteria produce methane, which can be burnt for electricity
- the digested sludge can be used for fertilisers as it is rich in nutrients
- air is bubbled through the liquid effluent, to allow aerobic bacteria to multiply, and in the presence of oxygen the aerobic bacteria can digest the organic molecules, and harmful microorganisms
- after this, the liquid effluent can be safely discharged into rivers and seas
describe the ways that potable water can be produces but comment and the relative easiness for each method
using ground water from aquifers
- this is safe to drink, once it has been treated with chlorine
- however, aquifers can sometimes be polluted, so the water needs to be tested carefully
- potable water can also be produced directly from waste water, but this takes many purification steps, and so is only done in places where water is scarce
- salt water needs to be desalinated to produce potable water
- desalination requires lots of energy, and is expensive
what are the ways that copper can be extracted from ores
- by using sulfuric acid
- sulfuric acid is used to produce copper sulfate solution, before extracting the copper metal
- another way is smelting
- the copper ore is heated to a high temperature, in a furnace with air, to produce impure copper
- the impure copper is then used in electrolysis to make pure copper
- this requires lots of energy and electricity, and is expensive
now that copper is becoming scarce what are the ways to extract copper
from low-grade ores include phytomining, and bioleaching